In recent years, in order to increase the yield of plants, the plants are usually placed in a greenhouse, and lamps are equipped in the greenhouse to control the illumination time of the plants. However, the heat insulation of the films commonly used for constructing the greenhouse is poor, resulting in an excessively high temperature in the greenhouse. Therefore, an additional air conditioning system is required to cool the greenhouse, resulting in increased production costs.
Generally speaking, in order to manufacture a film having a high heat insulation coefficient, a conventional method is to apply a layer of coating on a polyethylene (PE) film or on a polyethylene terephthalate (PET) film, so as to improve the overall heat insulation capability of the PE film or the PET film by means of the high heat insulation property of the coating.
In selection of a heat insulation material, it seems that a mesoporous silica material can be used to solve the problem that the heat insulation of the films commonly used is poor. Since the contact between the solid particles of the mesoporous silica material is less, and the size of the pores of the mesoporous silica material is less than the mean free path of intermolecular collisions, the heat conduction path in the mesoporous silica material is restricted, and thereby the thermal conductivity of the gas is reduced. However, since the film-forming ability of the mesoporous silica material is poor, how to apply the mesoporous silica material in a heat insulation film has become a problem to be solved by researchers.
In addition, the commonly used films have the problems that the transmissivity of the films is not good, and water drops are easily condensed, resulting in an insufficient quantity of illumination. Therefore, additional lamps are required, resulting in increased production costs.